csswg-drafts/css-module/Overview.src.html at 827781225248abb951dc7d94961315e310a27200 · w3c/csswg-drafts · GitHub

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
<!DOCTYPE html>
<html lang="en">
<head>
  <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
  <title>CSS TEMPLATE Module Level N</title>
  <link rel=contents href="#contents">
  <link rel=index href="#index">
  <link rel="stylesheet" type="text/css" href="../default.css">
  <link href="../csslogo.ico" rel="shortcut icon" type="image/x-icon">
  <link rel="stylesheet" type="text/css" href="https://www.w3.org/StyleSheets/TR/W3C-ED.css">
  <style type="text/css">
    /* delete this block when you've cleared out all the .replaceme elements */
    .replaceme {
      border: solid red;
      padding: 0 0.5em;
      margin: 0 0.1em;
      background: yellow;
      color: green;
    }
    .replaceme:before {
       content: "FIXME(";
       color: black;
    }
    .replaceme:after {
       content: ")";
       color: black;
    }
  </style>
</head>

<body class="h-entry">

<div class="head">
<!--logo-->

<h1 class="p-name">[TITLE]</h1>

<h2 class="no-num no-toc">[LONGSTATUS] <time class="dt-updated" datetime="[CDATE]">[DATE]</time> <!-- for HTML4.x doctypes: <span class="dt-updated"><span class="value-title" title="[CDATE]">[DATE]</span></span> --> </h2>
<dl>
  <dt>This version:
    <dd><a class="u-url" href="[VERSION]">[VERSION]</a>

  <dt>Latest version:
    <dd><a href="[LATEST]"><var class=replaceme>https://www.w3.org/TR/css-module/</var></a>

  <dt>Editor's draft:
    <dd><a href="https://drafts.csswg.org/[SHORTNAME]/">https://drafts.csswg.org/[SHORTNAME]/</a>
    (<a href="https://hg.csswg.org/drafts/log/tip/[SHORTNAME]/Overview.src.html">change log</a>)

  <dt>Previous version:
    <dd><a href="http://www.w3.org/PreviousVersionURI">
    http://www.w3.org/PreviousVersionURI</a>

  <dt>Issue Tracking:</dt>
    <dd><a rel="issues" href="http://www.w3.org/Style/CSS/Tracker/products/FIXME">http://www.w3.org/Style/CSS/Tracker/products/FIXME</a>
<!-- or use the wiki:
    <dd><a rel="issues" href="http://wiki.csswg.org/spec/cssN-FIXME"
           >http://wiki.csswg.org/spec/cssN-FIXME</a></dd>
-->

  <dt>Feedback:</dt>
    <dd><a href="mailto:www-style@w3.org?subject=%5BSHORTNAME%5D%20feedback"
         >www-style@w3.org</a>
         with subject line &ldquo;<kbd>[[SHORTNAME]]
         <var>&hellip; message topic &hellip;</var></kbd>&rdquo;
         (<a rel="discussion" href="http://lists.w3.org/Archives/Public/www-style/"
           >archives</a>)

  <dt>Editors:
    <dd class="p-author h-card vcard">
      <a class="p-name fn u-url url" rel="author"
         href="[editor1 personal URL (opt.)]">[editor1 name]</a>,
      <a class="p-org org h-org" href="[affiliation/co. home page (opt.)]">[affiliation (opt.)]</a>,
      <span class="u-email email">[email address (opt.)]</span>
    <dd class="p-author h-card vcard">
      <span class="p-name fn">[editor2 name]</span>,
      <span class="p-org org">[affiliation (opt.)]</span>,
      <span class="u-email email">[email address (opt.)]</span>
</dl>

<!--copyright-->

<hr title="Separator for header">
</div>

<h2 class="no-num no-toc" id="abstract">Abstract</h2>

  <p>
  <span class="p-summary">
  This module contains the features of CSS relating to
  <var class="replaceme">DESCRIBE HERE</var>.
  </span>

  <a href="https://www.w3.org/TR/CSS/">CSS</a> is a language for describing
  the rendering of structured documents (such as HTML and XML) on screen, on
  paper, in speech, etc.

<h2 class="no-num no-toc" id="status">Status of this document</h2>

<!--status-->

<p>The following features are at risk: &hellip;

<nav id="toc">
<h2 class="no-num no-toc" id="contents">
Table of Contents</h2>

<!--toc-->
</nav>

<h2 id="intro">
Introduction</h2>

  <p><em>This section is not normative.</em>

  <p><var class="replaceme">Provide background, motivation, etc.</var></p>

<h3 id="placement">
Module interactions</h3>

  <p class="replaceme">Explain, normatively, how this module affects the definition of CSS.</p>

  <p>This module replaces and extends the <var class="replaceme">SUMMARIZE HERE</var>
  features defined in [[!CSS21]] sections <var class="replaceme">W.X and Y.Z</var>.

  <p class="replaceme">All properties in this module apply to the <code>::first-line</code> and
  <code>::first-letter</code> pseudo-elements.
  <!-- HANDLE, THEN REMOVE THIS COMMENT
     Properties that affect box layout should be excluded from ::first-line.
     Properties that take things out-of-flow or alter box construction should
     be excluded from both ::first-line and ::first-letter. (A special exception
     is made for float on ::first-letter, which is defined to emulate drop-caps.)
     Examples of ::first-line / ::first-letter statements:
     https://drafts.csswg.org/css3-background/#placement
       (All properties apply to ::first-letter; some apply to ::first-line)
  -->

<h3 id="values">
Values</h3>

  <p>This specification follows the
  <a href="https://www.w3.org/TR/CSS21/about.html#property-defs">CSS property
  definition conventions</a> from [[!CSS21]]. Value types not defined in
  this specification are defined in CSS Level 2 Revision 1 [[!CSS21]].
  Other CSS modules may expand the definitions of these value types: for
  example [[CSS3VAL]], when combined with this module, expands the
  definition of the <var>&lt;length&gt;</var> value type as used in this specification.</p>

  <p>In addition to the property-specific values listed in their definitions,
  all properties defined in this specification also accept the
  <a href="https://www.w3.org/TR/CSS21/cascade.html#value-def-inherit">inherit</a>
  keyword as their property value. For readability it has not been repeated
  explicitly.

<h2 id="sample-topic">
Sample section</h2>

  <p>Look at the mark-up in this section for examples. See the <a
  href="https://www.w3.org/Style/Group/css3-src/bin/README">documentation</a> for more precise instructions. The
  companion of this template shows the <a href="Overview.html">processed
  result</a>.</p>

  <p>To refer to HTML, use [[HTML40]] (note the double square brackets). To
  make a normative reference, insert a &ldquo;!&rdquo;, like this:
  [[!CSS3SYN]] The currently available
  <a href="http://dev.w3.org/CSS/biblio/biblio.ref">list of bibliographic data</a>
  can of course be extended.</p>

  <p>We write about a property such as 'display-model' like this and
  about a piece of CSS code like this: ''foo: bar''. Inline HTML and XML
  are similar, but use the CODE element: <code
  class=html>&lt;blockquote&gt;...&lt;/blockquote&gt;</code> and <code
  class=xml>&lt;r:xyz&gt;...&lt;/r:xyz&gt;</code>.

  <p class=note>Note that the property will automatically be linked to its
  definition.

  <p>To put <span class=index>terms</span> into the <span
  class=index-def>index</span>, there are many <span class=index
  title="variant">variants</span>, but hopefully the <span class=index
  title="simple|simpler|simplest">simplest</span> will be the most <span
  class=index title="frequency::common">common</span>. But a little more
  <span class=index title="work|resource::time spent">work</span> now
  will help many people for a long time.

  <p class=note>Note that you can add non-normative notes like this.

  <p>Of course, multi-paragraph notes are also possible: just enclose them in a
  DIV:

  <div class=note>
    <p>Note that this note is a multi-paragraph note.</p>
    <p>It doesn't <em>need</em> to have two paragraphs, but it could.</p>
  </div>

  <p>Displayed examples come in eight different types: CSS examples that need
  no separate paragraph of explanation are put in a simple PRE:

  <pre class=example>EM { font-style: italic }</pre>

  <p>CSS examples that need extra text need a DIV.</p>

  <div class=example>
  <p>The following example is the same as the previous one, but now it is
  explained:</p>
  <pre>EM { font-style: italic }</pre>
  </div>

  <p>Illegal CSS examples (examples of errors) are the same, but with class
  "illegal example". Examples of HTML and XML code have class "html" and "xml"
  respectively, but are otherwise ditto.</p>

  <p>A formal definition of a property looks like this:</p>

<h3 id="the-display-model">
Internal display model: the 'display-inside' property</h3>

  <table class=propdef>
    <tr>
      <th>Name:
      <td><dfn>display-inside</dfn>
    <tr>
      <th><a href="#values">Value</a>:
      <td>inline-inside | block-inside | table | ruby | icon
    <tr>
      <th>Initial:
      <td>text
    <tr>
      <th>Applies to:
      <td>all elements
    <tr>
      <th>Inherited:
      <td>no
    <tr>
      <th>Percentages:
      <td>N/A
    <tr>
      <th>Computed&nbsp;value:
      <td>specified value
    <tr>
      <th>Animatable:
      <td>no
    <tr>
      <th>Canonical order:
      <td><abbr title="follows order of property value definition">per grammar</abbr>
  </table>

  <dl>
    <dt><dfn>''value-name''</dfn></dt>
      <dd>Define values using a DL
  </dl>

  <p><dfn>Cross-references</dfn> are created by enclosing a term or phrase in
  &lt;dfn&gt; (like the word <em>cross-references</em> earlier in this
  sentence). Then any element with the same content will automatically be
  linked. For example: <span>cross-references</span>.</p>

  <p>And a figure with a caption is done like this:

  <div class=figure>
  <p><img src="corner.png"
  alt="A table with a caption above it; both have margins and the margins between them are collapsed, as is normal for vertical margins.">

  <p class=caption>Just a random image. SVG would be nice, but maybe SVG
  isn't sufficiently easy to use yet. W3C prefers PNG over GIF (obviously,
  since PNG is a W3C Rec).
  </div>

  <p>Don't forget to write the longdesc.

  <p class=issue>An open issue or editorial remark is OK in a WD, but
  they should be resolved/removed before the document goes to
  &ldquo;CR&rdquo; (Candidate Recommendation). Use
  class=&ldquo;issue&rdquo;.

<h2 id="conformance">
Conformance</h2>

<h3 id="conventions">
Document conventions</h3>

  <p>Conformance requirements are expressed with a combination of
  descriptive assertions and RFC 2119 terminology. The key words “MUST”,
  “MUST NOT”, “REQUIRED”, “SHALL”, “SHALL NOT”, “SHOULD”, “SHOULD NOT”,
  “RECOMMENDED”, “MAY”, and “OPTIONAL” in the normative parts of this
  document are to be interpreted as described in RFC 2119.
  However, for readability, these words do not appear in all uppercase
  letters in this specification.

  <p>All of the text of this specification is normative except sections
  explicitly marked as non-normative, examples, and notes. [[!RFC2119]]</p>

  <p>Examples in this specification are introduced with the words “for example”
  or are set apart from the normative text with <code>class="example"</code>,
  like this:

  <div class="example">
    <p>This is an example of an informative example.</p>
  </div>

  <p>Informative notes begin with the word “Note” and are set apart from the
  normative text with <code>class="note"</code>, like this:

  <p class="note">Note, this is an informative note.</p>

<h3 id="conformance-classes">
Conformance classes</h3>

  <p>Conformance to [TITLE]
  is defined for three conformance classes:
  <dl>
    <dt><dfn title="style sheet!!as conformance class">style sheet</dfn>
      <dd>A <a href="https://www.w3.org/TR/CSS21/conform.html#style-sheet">CSS
      style sheet</a>.
    <dt><dfn>renderer</dfn></dt>
      <dd>A <a href="https://www.w3.org/TR/CSS21/conform.html#user-agent">UA</a>
      that interprets the semantics of a style sheet and renders
      documents that use them.
    <dt><dfn id="authoring-tool">authoring tool</dfn></dt>
      <dd>A <a href="https://www.w3.org/TR/CSS21/conform.html#user-agent">UA</a>
     
72A1
 that writes a style sheet.
  </dl>

  <p>A style sheet is conformant to [TITLE]
  if all of its statements that use syntax defined in this module are valid
  according to the generic CSS grammar and the individual grammars of each
  feature defined in this module.

  <p>A renderer is conformant to [TITLE]
  if, in addition to interpreting the style sheet as defined by the
  appropriate specifications, it supports all the features defined
  by [TITLE] by parsing them correctly
  and rendering the document accordingly. However, the inability of a
  UA to correctly render a document due to limitations of the device
  does not make the UA non-conformant. (For example, a UA is not
  required to render color on a monochrome monitor.)

  <p>An authoring tool is conformant to [TITLE]
  if it writes style sheets that are syntactically correct according to the
  generic CSS grammar and the individual grammars of each feature in
  this module, and meet all other conformance requirements of style sheets
  as described in this module.

<h3 id="partial">
Partial implementations</h3>

  <p>So that authors can exploit the forward-compatible parsing rules to
  assign fallback values, CSS renderers <strong>must</strong>
  treat as invalid (and <a href="https://www.w3.org/TR/CSS21/conform.html#ignore">ignore
  as appropriate</a>) any at-rules, properties, property values, keywords,
  and other syntactic constructs for which they have no usable level of
  support. In particular, user agents <strong>must not</strong> selectively
  ignore unsupported component values and honor supported values in a single
  multi-value property declaration: if any value is considered invalid
  (as unsupported values must be), CSS requires that the entire declaration
  be ignored.</p>

<h3 id="experimental">
Experimental implementations</h3>

  <p>To avoid clashes with future CSS features, the CSS2.1 specification
  reserves a <a href="https://www.w3.org/TR/CSS21/syndata.html#vendor-keywords">prefixed
  syntax</a> for proprietary and experimental extensions to CSS.

  <p>Prior to a specification reaching the Candidate Recommendation stage
  in the W3C process, all implementations of a CSS feature are considered
  experimental. The CSS Working Group recommends that implementations
  use a vendor-prefixed syntax for such features, including those in
  W3C Working Drafts. This avoids incompatibilities with future changes
  in the draft.
  </p>

<h3 id="testing">
Non-experimental implementations</h3>

  <p>Once a specification reaches the Candidate Recommendation stage,
  non-experimental implementations are possible, and implementors should
  release an unprefixed implementation of any CR-level feature they
  can demonstrate to be correctly implemented according to spec.

  <p>To establish and maintain the interoperability of CSS across
  implementations, the CSS Working Group requests that non-experimental
  CSS renderers submit an implementation report (and, if necessary, the
  testcases used for that implementation report) to the W3C before
  releasing an unprefixed implementation of any CSS features. Testcases
  submitted to W3C are subject to review and correction by the CSS
  Working Group.

  <p>Further information on submitting testcases and implementation reports
  can be found from on the CSS Working Group's website at
  <a href="http://www.w3.org/Style/CSS/Test/">http://www.w3.org/Style/CSS/Test/</a>.
  Questions should be directed to the
  <a href="http://lists.w3.org/Archives/Public/public-css-testsuite">public-css-testsuite@w3.org</a>
  mailing list.

<h3 id="cr-exit-criteria">
CR exit criteria</h3>

  <p class="replaceme">Remove this section unless/until the module is in CR.</p>

  <!-- This text was <a href="http://www.w3.org/Style/CSS/Tracker/actions/44"> decided on 2008-06-04.</a> -->

  <p>
  For this specification to be advanced to Proposed Recommendation,
  there must be at least two independent, interoperable implementations
  of each feature. Each feature may be implemented by a different set of
  products, there is no requirement that all features be implemented by
  a single product. For the purposes of this criterion, we define the
  following terms:

  <dl>
    <dt>independent <dd>each implementation must be developed by a
    different party and cannot share, reuse, or derive from code
    used by another qualifying implementation. Sections of code that
    have no bearing on the implementation of this specification are
    exempt from this requirement.

    <dt>interoperable <dd>passing the respective test case(s) in the
    official CSS test suite, or, if the implementation is not a Web
    browser, an equivalent test. Every relevant test in the test
    suite should have an equivalent test created if such a user
    agent (UA) is to be used to claim interoperability. In addition
    if such a UA is to be used to claim interoperability, then there
    must one or more additional UAs which can also pass those
    equivalent tests in the same way for the purpose of
    interoperability. The equivalent tests must be made publicly
    available for the purposes of peer review.


    <ol class=inline>
      <li>implements the specification.

      <li>is available to the general public. The implementation may
      be a shipping product or other publicly available version
      (i.e., beta version, preview release, or “nightly build”).
      Non-shipping product releases must have implemented the
      feature(s) for a period of at least one month in order to
      demonstrate stability.

      <li>is not experimental (i.e., a version specifically designed
      to pass the test suite and is not intended for normal usage
      going forward).
    </ol>
  </dl>

  <p>The specification will remain Candidate Recommendation for at least
  six months.

<h2 class=no-num id="acknowledgments">
Acknowledgments</h2>

  <p><var class="replaceme">[acknowledgments]</var></p>

<h2 class=no-num id="references">
References</h2>

<h3 class="no-num" id="normative-references">
Normative references</h3>
<!--normative-->

<h3 class="no-num" id="other-references">
Other references</h3>
<!--informative-->

<h2 class="no-num" id="index">
Index</h2>
<!--index-->

<h2 class="no-num" id="property-index">
Property index</h2>
<!-- properties -->

</body>
</html>
<!-- Keep this comment at the end of the file
Local variables:
mode: sgml
sgml-declaration:"~/SGML/HTML4.decl"
sgml-default-doctype-name:"html"
sgml-minimize-attributes:t
sgml-nofill-elements:("pre" "style" "br")
sgml-live-element-indicator:t
sgml-omittag:nil
sgml-shorttag:nil
sgml-namecase-general:t
sgml-general-insert-case:lower
sgml-always-quote-attributes:t
sgml-indent-step:nil
sgml-indent-data:t
sgml-parent-document:nil
sgml-exposed-tags:nil
sgml-local-catalogs:nil
sgml-local-ecat-files:nil
End:
-->